Cognitive development refers to a person's thought processes and the development of mental traits. It looks at how a person thinks, perceives, gains understanding and together with information processing, reasoning, imagination and memory it is how a person interacts with the world from childhood through to adulthood. This development has been measured and studied in a variety of ways over many years and two of the more influential theorists, Piaget and Bruner both agreed that cognitive development took place in stages. However, their theories are fundamentally different.
Piaget's theory was first published in 1952 and he was the first to propose that there were set steps and sequences to a child's intellectual development which results from an active, dynamic interplay between child and environment. His theory grew from years of observational studies of children in their natural environment as opposed to laboratory experiments conducted by other scholars in the same field, although some experimental data was also used. Piaget believed in a staged theory of development, in other words, that older children think qualitatively differently to younger children and that all children progress through four stages: sensorimotor, preoperational, concrete operational and formal operational.
Development is the combined results of the brain and nervous system maturing and the increased knowledge acquired from schemas. Schema's are past experiences that help one to interpret, understand and adapt to new environments and experiences. In Piaget's view, new information is used to modify, add to, or change previously existing schemas in a process known as adaption which is defined as an organism's ability to fit in with its environment. This adaption by the child results in two fundamental actions Piaget termed assimilation and accommodation. Assimilation is the process of taking new information into a previously existing schema. However, the process is somewhat subjective as humans tend to modify experience and information somewhat to fit in with pre-existing beliefs. Accommodation is the changing or altering of existing schemas with this new information and development of a new schema. Using Piaget's theory, cognitive development involves an ongoing attempt to achieve a balance between assimilation and accommodation that he termed equilibration.
Piaget's cognitive development series of four distinct stages are characterized by increasingly sophisticated and abstract levels of thought which always occur in the same order with each building on what was learned previously. Piaget believed each stage of development occurs as a result of interaction between maturation and environment and that intelligence is the ability to adapt. Piaget's theory differs from other theories in several ways: it is concerned with children rather than all learners and he underestimated the ability of children as tasks were methodologically flawed, it focuses on development rather than learning per se so does not address learning of information or specific behaviours, it proposes discrete stages of development marked by qualitative differences rather than a gradual increase in number and complexity and he underestimated the impact of culture with his tasks being culturally biased.
One of the problems of Piaget's theory is that it's been understood or taken to mean that before children reach the various stages he sets out the children are not capable (no matter how bright) of understanding things in certain ways. In contrast, Bruner observes that the process of constructing knowledge of the world is not done in isolation but rather within a social context and notes that "there is no unique sequence for all learners, and the optimum in any particular case will depend upon a variety of factors, including past learning, stage of development, nature of the material, and individual differences."
Bruner built on Vygotsky's social constructional theory from the 1930's which fell into three general claims; higher mental functioning in individuals emerged out of social processes (culture), secondly, social and psychological processes are fundamentally shaped by cultural tools (language) and lastly, the developmental Zone of Proximal Development (ZPD). The ZPD is defined as the difference between problem-solving the child is capable of performing independently and the same capabilities with guidance and collaboration. Like Piaget, Bruner said that children have an innate capacity and that cognitive abilities develop through interaction. However, unlike Piaget, Bruner argued that these social factors were important for cognitive growth. These underpin the concept of scaffolding; the help given to a child that supports learning whereby a child is shown how to do something so the child can accomplish the task individually. The scaffolding is a temporary support mechanism that helps the child: understand new ideas, complete new tasks, motivates and encourages the child so they can achieve higher levels of development. In contrast to Piaget's four stages, Bruner suggested a socio-cognitive three stage theory: the enactive mode, the iconic mode and the symbolic mode.
Bruner had a particular interested in cognitive development of children in relation to education during the 1950's. Bruner stressed the importance of the role of social exchanges between the child and adult through language and that without this, thought is limited. Language forms the basis of understanding through pre-linguistic processes (games and rituals) which are gradually replaced as the adults adds information and these are then replaced by linguistic modes of communication. Whilst Bruner's theory is much narrower in scope that Piaget's, Bruner's ideas have been applied more directly to education. Bruner's work was instrumental in the development of educational programmes in the USA. He also became involved in the design and implementation of the MACOS project; later critiqued as difficult to implement due to the degree of sophistication and learning needed from teachers and due to the ability and motivation needed from students for it to succeed.
Piaget suggested that children learnt in a set series of stages and could not learn things deemed too difficult, however, unlike Piaget's, Bruner did not contend that these stages were necessarily age-dependent, or invariant. Bruner argued that any subject can be taught effectively at any stage of development and with the emphasis on social interaction and language. This underpins the philosophy of a spiral curriculum in education whereby a subject is revisted repeatedly, building knowledge and depth each time appropriate to the level of the child. For example, it would not be appropriate to teach a three year old complex physics, however, Bruner contented that they could be taught some principles of physics (e.g., force, mass, momentum, friction) in enactive form and later repeated in iconic, then symbolic form. Bruner's theories on enactive, iconic, and symbolic stages may also be applicable to adults learning unfamiliar material where in contrast Piaget theories relate to children only.
Aswell as Piaget and Bruner, other major theorists such as Gesell, Erikson and Spock also believe there are stages and periods of development, but each emphasizes a different approach to the study of a child's thinking and learning patterns. Gesell's theory is that heredity promotes development in a preordained sequence with few individual differences. He deemphasizes individual differences among children and stresses the importance of maturation following an inherited timetable; abilities and skills emerge in a preordained sequence. Although Erikson and Spock also think of cognitive development in terms of stages, in contrast, they emphasize the emotional development of children.